Linear guide

ABSTRACT

A return cover provided with a ball circulation path is attached to a slider, a lubricant retainer made up from a porous elastic body and in sliding contact with a guide rail of a body is supported by the return cover, and the lubricant retainer is provided therein with a lubricant storage space filled with lubricant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2021-063426 filed on Apr. 2, 2021, thecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a linear guide having lubricant to besupplied to a guide rail.

Description of the Related Art

Conventionally, there has been known a linear guide in which a sliderdriven by an actuator is supported on a body via rolling elements suchas balls. For example, JP 2001-041305 A discloses an actuator that rollsand circulates a plurality of balls between a base and a slider drivenby a motor.

There is also known such a linear guide having a structure for supplyinglubricant to a guide rail serving as a rolling surface for a rollingelement. For example, an actuator disclosed in JP 2001-041305 A includesa ball return member constituting a part of a circulation path for aplurality of balls. A lubricating oil supply unit containing alubricating oil-containing polymer member is attached to the ball returnmember.

SUMMARY OF THE INVENTION

However, there is a limit to the amount of lubricant impregnated intothe lubricant-containing member. In the conventional linear guide, whenall of the lubricant impregnated in the lubricant-containing member isconsumed, supply of the lubricant to the guide rail is stopped.Therefore, maintenance such as replacement of the lubricant-containingmember is necessary.

The present invention has the object of solving the aforementionedproblems.

The linear guide according to the present invention has a configurationin which a plurality of balls are arranged between a guide rail of abody and a guide rail of a slider, and a return cover including a ballcirculation path is attached to the slider. A valve retainer made upfrom a porous elastic body and being in a sliding contact with the guiderail of the body is supported by the return cover, and a lubricantretainer has a lubricant storage space filled with a lubricant inside.

According to the linear guide, each time the lubricant in the lubricantretainer is consumed, the lubricant retainer is replenished with thelubricant filled in the lubricant storage space. Therefore, thelubricant can be supplied to the guide rail of the body over a longperiod of time.

Since the lubricant retainer of the linear guide according to thepresent invention includes therein the lubricant storage space filledwith the lubricant, a state in which the lubricant retainer issufficiently impregnated with the lubricant is maintained over a longperiod of time, and the lubricant can be continuously supplied to theguide rail of the body.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings, in which apreferred embodiment of the present invention is shown by way ofillustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a linear guide according to a first embodimentof the present invention.

FIG. 2 is an external view of the linear guide shown in FIG. 1.

FIG. 3 is an exploded view of a part of the linear guide shown in FIG.1.

FIG. 4 is a cross-sectional view taken along a line IV-IV of the linearguide of FIG. 1.

FIG. 5 is a cross-sectional view taken along a line V-V of the linearguide of FIG. 1.

FIG. 6 is a partial cross-sectional view of the linear guide of FIG. 1including a retainer.

FIG. 7 is a partially developed view of a linear guide according to asecond embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of the linear guide of FIG. 7including a retainer.

DESCRIPTION OF THE INVENTION

In the following description, when the terms in relation to the up,down, left, and right directions are used, for the sake of convenience,such terms refer to the directions shown in FIG. 1. However, the actualarrangement of the respective component members is not necessarilylimited to this feature.

First Embodiment

A linear guide 10 according to a first embodiment of the presentinvention will be described with reference to FIGS. 1 to 6. The linearguide 10 includes a body 12 to which a drive source (not shown) such asan air cylinder or an electric motor is attached, and a slider 18 thatis linearly reciprocated by the drive source.

As shown in FIGS. 1 to 3, the slider 18 includes a rectangularparallelepiped slider main body 20, a table portion 22 formed integrallywith the slider main body 20, and a pair of return covers 26. The returncover 26 is attached to both ends of the slider main body 20 in thelongitudinal direction (direction A). A workpiece can be placed on thetable portion 22. Slider guide rails 24 extending in the longitudinaldirection of the slider main body 20 are attached to both side surfacesof the slider main body 20. The slider main body 20 has a hole portion20 a penetrating in the longitudinal direction. A drive member (notshown) such as a ball screw for driving the slider 18 is coupled to thehole portion 20 a.

Each slider guide rail 24 includes a pair of transfer surfaces 24 aarranged in the up-down direction. A ball 48 can roll on the transfersurfaces 24 a. The slider main body 20 internally has a ball circulationpath 20 b having a linear track at a position corresponding to thetransfer surface 24 a. That is, the slider main body 20 has a total offour linear ball circulation paths 20 b in the vertical and horizontaldirections.

The body 12 is a member having a U-shaped cross section that opensupward, and has a bottom wall portion 12 a and a pair of side wallportions 12 b. A body guide rail 14 extending in the longitudinaldirection (direction A) of the body 12 is attached to the inner sidesurface of each side wall portion 12 b. The body guide rail 14 isprovided with a convex portion 14 a projecting toward the slider guiderail 24 over the entire length. Transfer surfaces 14 b on which theballs 48 can roll are formed above and below the convex portion 14 a.The transfer surface 14 b faces the transfer surface 24 a of the sliderguide rail 24. A side cover 16 covering a side surface of the slidermain body 20 is attached to each side wall portion 12 b of the body 12.

The return cover 26 includes a flat plate-shaped lower plate portion 28,an upper plate portion 30 having a curved surface 30 a curved downward,and a pair of connecting wall portions 32 connecting the upper plateportion 30 to the lower plate portion 28. The curved surface 30 a of theupper plate portion 30 has a shape matching the hole portion 20 a of theslider main body 20. Note that the pair of return covers 26 have thesame structure.

As shown in FIGS. 4 and 5, the connecting wall portion 32 includes afirst wall portion 34, a second wall portion 36, and a third wallportion 38. The first wall portion 34 extends parallel to thelongitudinal direction of the slider main body 20. The second wallportion 36 extends in the width direction (direction B) of the returncover 26 from an end portion of the first wall portion 34. The thirdwall portion 38 is folded back from an end portion of the second wallportion 36 and extends parallel to the first wall portion 34. As shownin FIG. 3, the lower plate portion 28 has a step surface 28 c passingthrough a step portion 28 b in a region surrounded by the first wallportion 34, the second wall portion 36, and the third wall portion 38.

The second wall portion 36 of the connecting wall portion 32 includes aball circulation path 36 a. One end of the ball circulation path 36 a isconnected to the ball circulation path 20 b of the slider main body 20.The other end of the ball circulation path 36 a faces an end portion ofthe slider guide rail 24. The ball circulation path 36 a has asemi-circular track. That is, the second wall portion 36 includes atotal of four semi-circular ball circulation paths 36 a in the verticaland horizontal directions.

The lower plate portion 28 has bent portions 28 a bent obliquely upwardat both end portions in the widthwise direction (direction B). The upperplate portion 30 has bent portions 30 b bent in a mountain shape at bothend portions in the widthwise direction. An end portion of each bentportion 30 b of the upper plate portion 30 faces an end portion of eachbent portion 28 a of the lower plate portion 28 with a predeterminedclearance therebetween. Thus, opening portions 40 are formed in bothside surfaces of the return cover 26.

The return cover 26 is attached to the slider main body 20 by a pair ofattachment bolts 52. Specifically, a pressing plate 50 is disposedoutside the return cover 26. The pair of attachment bolts 52 areinserted through bolt insertion holes 50 a of the pressing plate 50 andbolt insertion holes 34 a of the first wall portion 34 of the returncover 26, and are screwed into bolt mounting holes 20 c of the slidermain body 20 (see FIG. 3).

The plurality of balls 48 are arranged in two rows in the up-downdirection between each body guide rail 14 and each slider guide rail 24.As the slider 18 moves, the plurality of balls 48 roll on the transfersurface 14 b of the body guide rail 14 and the transfer surface 24 a ofthe slider guide rail 24. The plurality of balls 48 move in the ballcirculation path 20 b of the slider main body 20 and in the ballcirculation path 36 a of the pair of return covers 26.

As shown in FIGS. 3 and 6, a polygonal columnar lubricant retainer 42 isdisposed between each bent portion 28 a of the lower plate portion 28 ofthe return cover 26 and each bent portion 30 b of the upper plateportion 30. The lubricant retainer 42 is made up from a porous elasticbody impregnated with lubricant such as grease.

An inner side surface 42 a of the lubricant retainer 42 abuts against aside surface of the first wall portion 34. One axial end surface(A1-direction end surface) of the lubricant retainer 42 abuts against anear 50 b formed at an end portion of the pressing plate 50. The otheraxial end surface (A2-direction end surface) of the lubricant retainer42 abuts against the step portion 28 b of the lower plate portion 28 andan end portion of the third wall portion 38. That is, the lubricantretainer 42 is positioned and supported by the lower plate portion 28,the upper plate portion 30, the connecting wall portion 32, and thepressing plate 50.

The lubricant retainer 42 includes a lubricant storage hole (lubricantstorage space) 44 having a circular cross section.

The lubricant storage hole 44 passes through the lubricant retainer 42in the axial direction. The lubricant retainer 42 is provided with aslit 46 formed so as to be connected to the lubricant storage hole 44 byits generating line. The slit 46 extends horizontally in a planar shape.The lubricant storage hole 44 is filled with lubricant (lubricating oil)such as grease. The slit 46 opens at an outer side surface 42 b and atboth end surfaces in the axial direction of the lubricant retainer 42.

The outer side surface 42 b of the lubricant retainer 42 protrudes fromthe opening portion 40 portion of the return cover 26 toward the bodyguide rail 14. The convex portion 14 a of the body guide rail 14elastically deforms the lubricant retainer 42 so as to push open theslit 46 of the lubricant retainer 42, and is inserted into the slit 46from the outer side surface 42 b of the lubricant retainer 42. One axialend side (A1-direction end portion) of the lubricant storage hole 44 isclosed by the pressing plate 50.

The lubricant retainer 42 is in sliding contact with the body guide rail14 at the outer side surface 42 b including the slit 46. With themovement of the slider 18, the lubricant retainer 42 is brought intocontact with the transfer surface 14 b of the body guide rail 14 atvarious positions in the longitudinal direction, and the lubricantimpregnated in the lubricant retainer 42 is uniformly supplied to thetransfer surface 14 b of the body guide rail 14. Since the lubricantstorage hole 44 is filled with a predetermined amount of lubricant, astate in which the lubricant retainer 42 is impregnated with a constantamount of lubricant is maintained over a long period of time.

When an excessive amount of lubricant is supplied to the body guide rail14, the lubricant is sucked by the lubricant retainer 42 as the slider18 moves. Therefore, the lubricant does not leak to the outside of thelinear guide 10. Further, when foreign matter such as dust adheres tothe body guide rail 14, the lubricant retainer 42 guides the foreignmatter to the outside of the linear guide 10 with the movement of theslider 18. Thus, the foreign matter can be removed.

According to the linear guide 10 of the present embodiment, thelubricant retainer 42 includes therein the lubricant storage hole 44that is filled with the lubricant. Therefore, a state in which thelubricant retainer 42 is sufficiently impregnated with the lubricant ismaintained over a long period of time, and the lubricant can becontinuously supplied to the guide rail 14 of the body 12.

In the present embodiment, the convex portion 14 a of the body guiderail 14 is inserted into the slit 46 of the lubricant retainer 42 whileelastically deforming the lubricant retainer 42. Alternatively, a recessmay be formed in the lubricant retainer 42 to receive the convex portion14 a of the body guide rail 14 in the natural state of the lubricantretainer 42. In the former case, there is an advantage thatmanufacturing of the lubricant retainer 42 is simple, and in the lattercase, there is an advantage that sliding resistance of the slider 18 issmall.

Second Embodiment

Next, a linear guide 60 according to a second embodiment of the presentinvention will be described with reference to FIGS. 7 and 8. In thelinear guide 60 according to the second embodiment, the structure of alubricant retainer 62 is different from that of the lubricant retainer42 of the first embodiment. The same structures as those of the linearguide 10 of the first embodiment are denoted by the same referencenumerals, and detailed description thereof will be omitted.

The lubricant retainer 62 is made of a porous elastic body impregnatedwith lubricant such as grease, and is a member formed in a thin-filmcylindrical shape having a uniform thickness. One side surface of thelubricant retainer 62 is provided with a slit-like notch 64 extending inthe horizontal direction. The other side surface of the lubricantretainer 62 includes two ridge portions 66 extending in the horizontaldirection and a trough portion 68 formed therebetween. The lubricantretainer 62 includes a lubricant storage space 70 inside, and thelubricant storage space 70 is filled with lubricant (lubricating oil)such as grease.

The lubricant retainer 62 is disposed between the bent portion 28 a ofthe lower plate portion 28 of the return cover 26 and the bent portion30 b of the upper plate portion 30. One side surface of the lubricantretainer 62 abuts against a side surface of the first wall portion 34 ofthe return cover 26. One of the opening end portions (A1-direction endportion) of the lubricant retainer 62 abuts on the ear 50 b of thepressing plate 50. The other opening end portion (A2-direction endportion) of the lubricant retainer 62 abuts against the step portion 28b of the lower plate portion 28 of the return cover 26 and an endportion of the third wall portion 38. That is, the lubricant retainer 62is positioned and supported by the lower plate portion 28, the upperplate portion 30, the connecting wall portion 32, and the pressing plate50.

The two ridge portions 66 of the lubricant retainer 62 protrude from theopening portion 40 of the return cover 26 toward the body guide rail 14.The convex portion 14 a of the body guide rail 14 is inserted into thetrough portion 68 of the lubricant retainer 62. An end portion of thelubricant storage space 70 in the A1 direction is closed by the pressingplate 50.

The lubricant retainer 62 is brought into sliding contact with thetransfer surface 14 b of the body guide rail 14 at two ridge portions66. As the slider 18 moves, the lubricant retainer 62 comes into contactwith the transfer surface 14 b of the body guide rail 14 at variouspositions in the longitudinal direction, and the lubricant impregnatedin the lubricant retainer 62 is uniformly supplied to the transfersurface 14 b of the body guide rail 14. Since the lubricant storagespace 70 is filled with a predetermined amount of lubricant, a state inwhich the lubricant retainer 62 is impregnated with a constant amount oflubricant is maintained over a long period of time.

According to the linear guide 60 of the present embodiment, thelubricant retainer 62 includes therein the lubricant storage space 70filled with lubricant. Therefore, a state in which the lubricantretainer 62 is sufficiently impregnated with lubricant is maintainedover a long period of time, and lubricant can be continuously suppliedto the guide rail 14 of the body 12. Further, since the lubricantretainer 62 is formed in a thin-film cylindrical shape, the volume ofthe lubricant storage space 70 provided inside the lubricant retainer 62can be increased as much as possible, and the filling amount oflubricant can be increased as much as possible.

The present invention is not limited to the embodiment described above,and various configurations may be adopted therein without deviating fromthe essence and gist of the invention.

What is claimed is:
 1. A linear guide comprising a plurality of ballsarranged between a guide rail of a body and a guide rail of a slider; areturn cover including a ball circulation path, the return coverattached to the slider; a lubricant retainer being made up from a porouselastic body, being in a sliding contact with the guide rail of thebody, being supported by the return cover, and being equipped with alubricant storage space filled with lubricant.
 2. The linear guideaccording to claim 1, wherein the lubricant retainer has a polygonalcolumnar shape, and the lubricant storage space is configured as alubricant storage hole penetrating the lubricant retainer in an axialdirection thereof and having a circular cross section.
 3. The linearguide according to claim 2, wherein an outer side surface of thelubricant retainer protrudes from an opening portion provided in thereturn cover toward the guide rail of the body.
 4. The linear guideaccording to claim 3, wherein the lubricant retainer is provided with aslit formed so as to be connected to the lubricant storage hole by agenerating line of the lubricant storage hole, and a convex portionprovided on the guide rail of the body is inserted into the slit.
 5. Thelinear guide according to claim 1, wherein the lubricant retainer is amember formed in a thin-film cylindrical shape.
 6. The linear guideaccording to claim 5, wherein a side face of the lubricant retainer isprovided with two ridge portions and a trough portion formed between thetwo ridge portions, and the two ridge portions project toward the guiderail of the body from an opening portion provided in the return cover.7. The linear guide according to claim 6, wherein a convex portionprovided on the guide rail of the body is inserted into the troughportion.